Grouping Plot and Fill in Same legend object

I have two plots of some mean value (hh) and two fill (he) plots of the confidence intervals for the associated mean values. I would like to be able to create only two legend entries instead of four so that the legend object is a combination of the plot and fill objects (Fill overlayed by the plot).

I've tried using hggroup to set parent figure handles to the plot and fill objects but I cannot get the legend to display the way I would like.

h1 = hggroup;
h2 = hggroup;

set(hh1, 'Parent', h1);
set(he3, 'Parent', h1);

set(hh2, 'Parent', h2);
set(he4, 'Parent', h2);

Is there a way to have overlayed legend entries for two different figure objects?

[Jonathan Epperl]

To clarify: You want the legend to display a little piece of a line and a filled area for each of your 2 data series?

[curoi]

Yeah, so that the patch shows up with the line overlayed as a single legend entry.

Answer 1

[Jonathan Epperl]

Okay, I hope, this helps you:

% -- generate some dummy data
t = linspace(0,1);
s1 = sin(5*t);
s2 = 3-cos(5*t);
s3 = s1.*s2;

Fx = [t fliplr(t)];
Fy1 = [s1+1 fliplr(s1)-1];
Fy2 = [s2+.5 fliplr(s2)-.1];
Fy3 = [s3+.1 fliplr(s3)-.5];
% ---

% -- draw your data, save all handles
hf = fill(Fx,Fy1,'g',Fx,Fy2,'y',Fx,Fy3,'m');
hold on
hl = plot(t,s1,'r',t,s2,'b',t,s3,'c');
hleg = legend(hf,'Sin','Cos','Sin*Cos');
hold off

% The children of the legend axes are the little graphics, and the labels
hc = flipud(get(hleg,'Children'));
% For some reason, Matlab lists the legend entries in reverse order in the
% handle of the Children.

% Now we draw a line of the appropriate color over every patch in the
% legend
for ii=1:3
  xp = get(hc(ii*2),'XData');
  yp = get(hc(ii*2),'YData');
  line(xp(2:3)+[-1 ;1]*(xp(3)-xp(2))/50,...   the line will be a little longer than the box
      [1 1]*(yp(2)+yp(1))/2,...   and sit right in the center vertically
      'Color',get(hl(ii),'Color'),... have the color of the corresponding line
      'Parent',hleg,... and be drawn into the legend axes
      'LineWidth',1);
end

Report back here if you need any help or explanation!

[Chad Greene]

Brilliant! Four years later and your answer is still helping people. Thanks Jonathan.

[liomsi liomsi]

with your exemple, get(hLegend,'Children') returns a 0×0 empty GraphicsPlaceholder array. Any idea why? I'm on Matlab R2017a.

[Arthur Vieira]

Same in R2020a. 'Children: [0×0 GraphicsPlaceholder]'